It's unlikely your problem and the problem the thread is about are the same, except for the symptom of high CPU usage. Bumping your old thread would've made more sense. Now the info about your problem is in two different places. (But also note this isn't an official support forum. If people don't have spare time or any ideas, you might not get a reply.)
For anyone else trying to follow this, here is the other thread which was mentioned:
[ul][li]DOpus 10 High CPU After Move or Copy Action[/li][/ul]
Is it happening when you change folders, or when you copy files, or both?
If it's both then the files (the ones in those folders, and the ones being copied) are probably triggering a bug in something that Opus uses to get information about the files. You mentioned PDF and Word documents in the other thread, so I'd guess it's a shell extension for extracting document information. Opus 10 will use them while Opus 9 ignored them. That's probably your difference.
Download the latest beta version of Opus (10.0.1.5 is linked in my signature) and install that.
Also download the latest version of ShellExView and run that. Sort by the Type column and see which MetaData and Property Handler extensions are installed on your system. Especially any non-Microsoft ones. They may point to the component that's causing the problem.
NOTE: Disabling them in ShellExView only affects Explorer, not Opus, as far as I can tell. So that won't help.